fax 01-972-952-9435.
AbstractThree installations of a new expandable casing patch in 5 ½" production casing are described. During field trials, 2,530 ft and 8,380 ft patches were installed in Wyoming and Texas gas wells previously shut-in due to corrosion leaks. The third application was in a new-drill well where a 205 ft patch isolated holes in casing from a perforating gun misfire. All three patches pressure-tested successfully thus enabling the wells to be fracture stimulated and produced.The product provides high-strength flush-bore expandable seals at the ends of a liner comprised of conventional OCTG pipes. Unique about this system is that the expansion mandrel becomes integral with the seal assembly to provide internal yield and collapse resistance comparable to the OCTG liner. A hydraulic setting tool powered via work string by a highpressure/low-volume pump (i.e., typical BOP or tubing tester) drives the expansion mandrel into the patch body.The product, built initially as a one-trip system, was simplified and made more reliable by running as a two-trip system. First, the lower expandable seals and polished bore receptacle are installed. Next, the spacer string with upper seal is stung into the lower receptacle and the upper seals are expanded.The system is versatile in that the upper expandable seal also provides a receptacle to which a tieback liner, production tubing or another patch can be attached.The paper highlights job design and execution including use of casing inspection logs, problems encountered, system improvements and best practices resulting from this work.